1. Field of the Invention
The invention in general relates to microwave power circuits, and more particularly to a device for combining the outputs of a plurality of high power amplifiers and combining them into a unitary signal.
2. Description of Related Art
In various RF circuits it is often necessary to amplify certain RF signals. However, a single amplifier may not be suitable due to space/weight constraints on a circuit board or due to power limitations of the amplifier. Accordingly, it is common to divide the signal into a plurality of identical signals and provide them to a like plurality of amplifiers. The outputs of these amplifiers are then combined to achieve the desired power rating which is greater than a single amplifier.
An RF combiner is a passive RF device used to add together, in equal proportions, two or more of these RF signals. One common type of combiner is the Wilkinson combiner which is easily added to a circuit board but however, takes up too much space on the board. Another type of combiner is the serial stripline coupler. This combiner is smaller than the Wilkinson combiner and utilizes a plurality of layers of dielectric with interposed striplines and ground planes. This structure results in a combiner which is complicated to manufacture and which exhibits undesired losses. The present invention obviates the drawbacks of current combiner circuits.